I need help with "imread"

I have a scanned document image https://www.dropbox.com/s/jy2wuvmqcj7b1eu/sf3r_0006.jpg. And when I read it into matlab using "imread" function most of the details are lost https://www.dropbox.com/s/2s75833ayfsie74/img.jpg. This happens to all my scanned pictures too. The pictures were scanned at 300dpi. Please any suggestions on how I can read the images without loosing the details would help. I'm using matlab 2011Ra.

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Jan
Jan il 29 Giu 2012

2 voti

Please explain how you get from "read into Matlab using "imread" to posted jpg. I'm convinced, that the picture is read correctly and only the display on the screen looks strange, because it is downsampled from 300 dpi to 72 or 96 dpi. If the "scanned" image is a black&white scan, such optical effects are expected.

4 Commenti

Aliyu Abdu
Aliyu Abdu il 29 Giu 2012
You are right. I just found out it was read into matlab correctly. When I zoomed in on the displayed image I can see all the details there. And it wasn't scanned in b&w but in color. Why wont the details show in normal display? What can I do to bring out the details?
Image Analyst
Image Analyst il 29 Giu 2012
You aren't seeing the image details in the displayed image merely because it's subsampled for display. I don't think that matters - it's just for aesthetics. Everyone knows that the more you shrink something down, the less details are visible. You can still do image processing on the full size image with all the details in it.
Jan
Jan il 29 Giu 2012
You can use IMRESIZE with e.g. the Lanczos3 (or Lanzcos3?! I will never be able to remember this important detail) smoothing to the screen resolution.
Aliyu Abdu
Aliyu Abdu il 29 Giu 2012
The "imresize" function worked. I used "imresize(x,[NaN n])". Thanks a lot. :)

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